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National 3994 Axle Differential Bearing - Rear or Rear Inner
Overview of National 3994 Axle Differential Bearing
The National 3994 axle differential bearing is engineered for Ford F-250 and F-350 models, providing reliable support for driveline components. This taper bearing cone is designed to meet precise specifications, ensuring proper fit and function in your vehicle's differential assembly.
- Cone bore diameter: 2.6250 inches (66.6750 mm)
- Cone length: 1.1850 inches (30.0990 mm)
- Cone radius: 0.2180 inches (5.5370 mm)
- Part type: Taper bearing cone
- Compatible with Ford F-250 and F-350 axle differentials
Technical Specifications and Features
The National 3994 axle differential bearing features a cone bore measuring 2.6250 inches (66.6750 mm), which ensures a precise fit within the differential assembly. The cone length of 1.1850 inches (30.0990 mm) and cone radius of 0.2180 inches (5.5370 mm) are critical dimensions that maintain proper bearing alignment and load distribution. This taper bearing cone is manufactured to meet OEM standards, providing consistent performance and durability for Ford F-250 and F-350 driveline systems.
Applications and Problem Solving
This axle differential bearing is specifically designed for use in Ford F-250 and F-350 models, making it suitable for maintenance or repair of the vehicle's differential assembly. It addresses common issues such as:
- Excessive bearing wear causing noise or vibration
- Improper bearing fit leading to premature failure
- Axle differential play affecting driveline stability
- Reduced load capacity impacting vehicle performance
- Corrosion or damage from extended use
Installation Notes and Tips
When installing the National 3994 axle differential bearing, ensure the following:
- Clean all mating surfaces thoroughly before installation
- Verify the cone bore and length dimensions match the vehicle specifications
- Use proper tools to avoid damaging the bearing cone during installation
- Apply appropriate lubrication to the bearing surfaces
- Check for correct preload and alignment after installation
Quality Assurance and Warranty
National manufactures the 3994 axle differential bearing to meet stringent quality standards, ensuring reliable performance in Ford F-250 and F-350 applications. While specific warranty details may vary, National products typically come with a limited warranty against defects in materials and workmanship. Refer to the product documentation for exact warranty terms.
| Brand | National |
|---|---|
| Part Number | 3994 |
| Cone Bore (Inch) | 2.6250 |
| Cone Bore (MM) | 66.6750 |
| Cone Length (Inch) | 1.1850 |
| Cone Length (MM) | 30.0990 |
| Cone Radius (Inch) | 0.2180 |
| Cone Radius (MM) | 5.5370 |
| Part Description | Taper Bearing Cone |
This part fits 29 vehicles. Search below:
| Year | Make | Model | Position | Notes |
|---|---|---|---|---|
| 1999 | Ford | F-250 | Rear Inner | Full-Floating; with 10.25 (in) Ring Gear |
| 1998 | Ford | F-250 | Rear Inner | Full-Floating; with 10.25 (in) Ring Gear |
| 1998 | Ford | F-350 | Rear Inner | |
| 1997 | Ford | F-250 | Rear Inner | Full-Floating; with 10.25 (in) Ring Gear |
| 1997 | Ford | F-350 | Rear Inner | |
| 1996 | Ford | F-250 | Rear Inner | Full-Floating; with 10.25 (in) Ring Gear |
| 1996 | Ford | F-350 | Rear Inner | |
| 1995 | Ford | F-250 | Rear Inner | Full-Floating; with 10.25 (in) Ring Gear |
| 1995 | Ford | F-350 | Rear Inner | |
| 1994 | Ford | F-250 | Rear Inner | Full-Floating; with 10.25 (in) Ring Gear |
| 1994 | Ford | F-350 | Rear Inner | |
| 1993 | Ford | F-250 | Rear Inner | Full-Floating; with 10.25 (in) Ring Gear |
| 1993 | Ford | F-350 | Rear Inner | |
| 1992 | Ford | F-250 | Rear Inner | Full-Floating; with 10.25 (in) Ring Gear |
| 1992 | Ford | F-350 | Rear Inner | |
| 1991 | Ford | F-250 | Rear Inner | Full-Floating; with 10.25 (in) Ring Gear |
| 1991 | Ford | F-350 | Rear Inner | |
| 1990 | Ford | F-250 | Rear Inner | Full-Floating; with 10.25 (in) Ring Gear |
| 1990 | Ford | F-350 | Rear Inner | |
| 1989 | Ford | F-250 | Rear Inner | Full-Floating; with 10.25 (in) Ring Gear |
| 1989 | Ford | F-350 | Rear Inner | |
| 1988 | Ford | F-250 | Rear Inner | Full-Floating; with 10.25 (in) Ring Gear |
| 1988 | Ford | F-350 | Rear Inner | |
| 1987 | Ford | F-250 | Rear Inner | Full-Floating; with 10.25 (in) Ring Gear |
| 1987 | Ford | F-350 | Rear Inner | |
| 1986 | Ford | F-250 | Rear Inner | Full-Floating; with 10.25 (in) Ring Gear |
| 1986 | Ford | F-350 | Rear Inner | |
| 1985 | Ford | F-250 | Rear Inner | Full-Floating; with 10.25 (in) Ring Gear |
| 1985 | Ford | F-350 | Rear Inner | with 10.25 (in) Ring Gear |
* Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
This part directly replaces or is cross-referenced with the following part numbers:
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.